An Air India flight from Delhi to Zurich was delayed on Sunday due to mandatory checks on Boeing 787-8 aircraft, resulting in its late arrival in Switzerland close to the night curfew, sources said on Monday.

The investigation into Air India flight 171 crash opens up questions into the many concerns surrounding Boeing's 787.

The crash happened just weeks after the company cut a deal with the U.S. government to avoid taking criminal responsibility for a pair of deadly crashes in 2018 and 2019.